Leveling by questing is fairly slow if you do everything.
On the other hand that is the hurry?
You can grind to speed things up but that is more boring as I see it.
With one tamriel you can do lots of stuff while leveling, even do trials
That was an shock for an returning player like me
Some others might have some more tips.
Note that then you reach 50, you start getting CP and they take far longer to max out
If you want quick levels, join a dolmen train in maps like Auridon. Usually just type x in zone chat and you'll be auto-invited to a team.
It's boring but you'll level very quickly.
IMO the big benefit to getting levelling out of the way is cosmetic. You can invest in decent looking clothes and then just play the game normally, without having to wear a mismatched assortment of whatever you happen to have looted, or settle for inferior motif crafted gear.